View Compilation Error

0_0_27152140_23646.cpp: In function 'int main()':
0_0_27152140_23646.cpp:2:150: error: 'mod' was not declared in this scope
 using namespace std; int main() { int n,ans; while(scanf("%d",&n)!=EOF) { ans=1; if(n>40)printf("0\n"); else { for(int i=1; i<=n; i++) { ans=(ans*i)%mod; } printf("%d\n",ans); } } return 0; }
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